Regulatory DNA changes have made a huge impact on the evolution of human-specific traits. A study in the latest issue of Nature covers not just the usual stuff, like what has been added in evolution to make us distinctly 'human', but rather what was lost.

We're obviously different from animals and the researchers set out to find some molecular occurrences that are present in chimpanzees and other mammals but not in people - they found 583, which they call hCONDELs, 510 which were validated, mostly in nonfunctional DNA. One instance sure to catch attention is deletion of a penile spine enhancer from the human androgen receptor (AR) gene, a change correlated with a change in human anatomy - namely loss of penile spines.

Even more interesting for junk science infomercials and spam emails regarding genitals in the future, they tested the AR expression pattern and found that the chimpanzee sequence drives 'significant' reporter gene expression when tested in human foreskin fibroblasts, which means that the pathways are still present in humans.

So why did this non-coding region of DNA get deleted? They say it is because humans became couples and adapted monogamous reproduction and morphological characteristics followed. So your penis has no spine because of pairbonding and increased paternal care. Thanks, wife!

Comments

So why did this non-coding region of DNA get deleted? They say it is
because humans became couples and adapted monogamous reproduction and
morphological characteristics followed. So your penis has no spine
because of pairbonding and increased paternal care. Thanks, wife!

I think it's important to note that these DNA changes reflect an increase in brain size as well as the loss of the penis spines. If you think about it, it makes good sense, since there was an obvious selection change with increased blood flow to the penis to power the second brain that men had evolved. :)